Fping¶

fping is a command-line tool used to send ICMP Echo Request packets to network hosts, similar to ping, but with a focus on performance and scripting. Unlike the standard ping which tests a single host at a time, fping can ping multiple hosts in parallel. It is an essential tool for network administrators and security professionals for network discovery, monitoring, and diagnostics.

Key Features¶

Parallel Pinging: Can ping a large number of hosts simultaneously, making it much faster for scanning entire subnets.
Script-Friendly Output: Provides various output formats that are easy to parse in shell scripts. It clearly indicates which hosts are up and which are down.
Flexible Host Input: Accepts hosts from the command line, from a file, or as a specified IP range.
Customizable Parameters: Allows users to configure the number of pings, interval between pings, timeout values, and packet size.

Installation¶

For Debian/Ubuntu-based Systems¶

You can install fping using the apt package manager.

Bash

sudo apt update
sudo apt install fping

For RHEL/CentOS-based Systems¶

Use the yum or dnf package manager to install fping. You may need to enable the EPEL (Extra Packages for Enterprise Linux) repository first.

Bash

sudo yum install epel-release
sudo yum install fping

Usage Examples¶

Below are common examples of how to use the fping command.

1. Ping a Single Host¶

To check if a single host is reachable, simply provide its IP address or hostname. The -a flag shows only systems that are alive.

Bash

fping -a 8.8.8.8

Output:

8.8.8.8 is alive

2. Ping Multiple Hosts¶

You can specify multiple hosts separated by spaces.

Bash

fping google.com 8.8.8.8 1.1.1.1

Output:

google.com is alive
1.1.1.1 is alive
8.8.8.8 is alive

3. Ping a Range of IP Addresses¶

Use the -g flag to generate a target list from a given IP range. This is useful for scanning a subnet.

Bash

fping -g 192.168.1.1 192.168.1.100

This command will ping every host from 192.168.1.1 to 192.168.1.100. To show only the hosts that are up, combine it with -a.

Bash

fping -a -g 192.168.1.0/24

This example uses CIDR notation to scan the entire /24 subnet.

4. Ping Hosts from a File¶

If you have a list of hosts in a text file (one per line), you can use fping to check all of them.

hosts.txt:

google.com
github.com
192.168.1.50

Command:

Bash

fping < hosts.txt

5. Customizing Ping Behavior¶

You can control the ping parameters using various flags:

-c <count>: Number of pings to send to each target.
-i <milliseconds>: Interval between pings to a single target (default is 25ms).
-t <milliseconds>: Timeout for waiting for a reply (default is 500ms).

Example: Send 3 pings to each host with a 1-second interval.

Bash

fping -c 3 -i 1000 google.com github.com

6. Show Unreachable Hosts¶

To get a list of hosts that are not responding, use the -u flag.

Bash

fping -u 192.168.1.99 192.168.1.100

Output:

192.168.1.99 is unreachable
192.168.1.100 is unreachable